JPH06285308A - Drum screen cleaning method and cleaning device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a cleaning method and a cleaning device for a drum screen, which can easily and effectively remove the oil and fat adhering to the drum screen. In a drum screen device capable of cleaning the screen portion 8, a valve 12 provided on a liquid discharge pipe portion 10 near the drum screen 3, a cleaning agent tank 21 installed outside, and a tank for cleaning agent from the tank to the inside of the drum screen. A pipe 19 for injecting a cleaning agent is provided, and at least the bottom of the screen portion is immersed in the cleaning agent, and the drum screen is rotated for cleaning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method for a drum screen, and more particularly to a cleaning method and a cleaning apparatus for a drum screen used in the treatment of night soil and waste water.

[0002]

2. Description of the Related Art Conventionally, as a method for cleaning a drum screen, high-pressure cleaning water alone has been used for cleaning. However, in recent years, with the spread of combined treatment septic tanks, septic tank sludge containing a large amount of oils and fats has come to be carried in in the night soil treatment facility, and the drum screen is clogged with the oils and fats in the septic tank sludge, and the treatment is The problem is that you can't do it. Further, since the oil and fat adhered to the drum screen is insoluble in water and firmly adhered, the oil and fat cannot be removed by washing with high pressure washing water, and the present situation is that they are removed manually. Furthermore, it is inevitable that the amount of urine collected by pumping will decrease and the amount of sludge in the septic tank will increase with the spread of washing with water in the future, and the above problems will occur more frequently in the future.

As a countermeasure against the above oil and fat, Japanese Patent Laid-Open No. 4-34
Japanese Patent No. 1309 discloses a method in which an alkaline agent is sprayed on a drum screen to decompose oil and fat components, and then rinsed with high-pressure washing water. The above method requires a plurality of pipes and nozzles for injecting the alkaline agent onto the drum screen, which complicates the apparatus, and injects the liquid onto a structure having many gap tubes such as the drum screen. However, most of the chemicals flow out from the screen in a short time, and a large amount of chemicals is required to obtain a sufficient cleaning effect.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a drum screen cleaning method and a cleaning device capable of easily and effectively removing oil and fat adhering to the drum screen. The task is to do.

[0005]

In order to solve the above problems, according to the present invention, in a method for cleaning a drum screen, at least the bottom of the screen portion of the drum screen is immersed in a cleaning agent, and the drum screen is rotated. It was decided to let. Further, in the present invention, in the drum screen device capable of cleaning the screen portion, a valve provided in the liquid discharge pipe portion near the drum screen,
A cleaning agent tank installed outside and a pipe for injecting the cleaning agent into the drum screen from the tank are provided.

As described above, in the present invention, when cleaning the drum screen, the valve provided in the liquid discharge pipe is closed so that at least a part of the screen portion of the drum screen is sufficiently immersed in the cleaning agent. And the contaminants adhering to the drum screen are washed while rotating the drum screen. As the detergent used in the present invention, a detergent containing a lipase having an action of decomposing oil and fat can be preferably used.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings, but the present invention is not limited thereto. Example 1 An example mainly applied to cleaning contamination due to oil and fat will be described with reference to the drawings. FIG. 1 is an overall view of a drum screen according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an essential part of the drum screen according to the embodiment. Further, FIG. 3 is a schematic diagram showing a cleaning agent supply system in the same embodiment, and FIG. 4 is a process diagram of sludge treatment using the drum screen of the present invention.

In FIG. 4, the septic tank sludge 1 flows into the receiving tank 2, then flows into the drum screen 3 to remove impurities and the like, and then flows into the storage tank 4. Subsequently, the septic tank sludge 1 stored in the storage tank 4 is put into the biological treatment process 5 in a fixed amount. Further, the impurities removed by the drum screen 3 are dehydrated by the screw press 6.

In FIG. 1, the drum screen 3 has a screen 8 which rotates around a horizontal axis inside a main body cover 7, a raw water supply pipe 9 for supplying septic tank sludge is provided inside the screen, and a septic tank is provided. The sludge is further supplied to the screen by the raw water supply gutter. The bottom part is provided with a filter pipe 10 for guiding the screen 8 filtrate to the storage tank and an overflow pipe 11 for returning the septic tank sludge 1 to the receiving tank 2 when the screen 8 is clogged. Further, valves 12 and 13 are provided in the filtration pipe 10 and the overflow pipe 11, respectively. This valve 12, 1
In order to save the amount of cleaning liquid, it is preferable to provide 3 as close to the upper part as possible. Valve 1 when cleaning the screen 8
After closing 2 and 13, respectively, a cleaning agent containing lipase as a main component and 10% glycerol and 10 mM calcium chloride was added to the inside of the drum screen from a cleaning agent supply pipe 14 (FIG. 2) provided outside the screen 8. Then, cleaning is performed for a certain period of time while rotating the screen 8.

The tip of the cleaning liquid pipe 14 may be of the shower type, but an ordinary pipe perforated pipe is preferable. this is,
This is because a shower type may cause clogging because a slight amount of precipitate may occur. An enzyme solution can be used as the cleaning solution, and since the enzyme easily attaches to SS, etc.,
It is possible to fill up from below the drum screen or the filtration pipe 10 and the overflow pipe 11, but in this case, the enzyme may be attached to the SS existing in the pipe and the effect on the important screen surface may be reduced. . Therefore, it is better to add from the top of the screen as shown.

2 and 3 in order to further ensure cleaning.
, A high-pressure washing water pipe 15 located outside the screen 8 is laid along the direction of the axis of rotation of the screen 8, and the high-pressure washing water pipe 15 has a plurality of high-pressure washing water jets for jetting high-pressure washing water toward the screen 8. A water jet nozzle 16 is provided. A water supply pipe 17 communicates with the high-pressure cleaning water pipe 15, and a high-pressure cleaning pump 18 is interposed in the middle of the water supply pipe 17. Further, a solution pipe 19 communicates with the detergent supply pipe 14, and the solution pipe 19 communicates with a detergent tank 21 via an injection pump 20.

2 and 3, when the screen 8 is clogged with the oil and fat contained in the septic tank sludge, the rotation of the screen 8 is once stopped and then the valves 12 and 13 are stopped.
Each of them is closed, and the cleaning agent containing lipase stored in the cleaning agent tank 21 as a main component and containing 10% glycerol and 10 mM calcium chloride is supplied by the injection pump 20 to the cleaning agent supply pipe 14 through the solution pipe 19 and the screen. 8
Is poured into the body cover 7 to such an extent that it is sufficiently immersed. Then, the screen 8 is immediately rotated. It is preferable to control the operation of the injection pump 20 or the opening / closing of the valve 22 attached to the cleaning liquid supply pipe 14 by the level sensor 23 in order to make the cleaning liquid level appropriate.

By the above operation, the oil and fat adhered to the screen 8 is decomposed by the action of lipase contained in the detergent. Then, after 10 to 60 minutes, the valves 12 and 13 are respectively opened to discharge the cleaning liquid, and the high-pressure cleaning pump 18 pumps the high-pressure cleaning water to the high-pressure cleaning water pipe 15 through the water supply pipe 17, and the high-pressure cleaning water injection nozzle 16 to the screen 8 High-pressure washing water is sprayed toward the surface to wash away the decomposed products remaining on the screen 8. In addition, it is preferable to spray high-pressure cleaning water before injecting the cleaning agent to wash away the filtrate adhering to the inside of the main body cover 7, and then inject the cleaning agent, so that the effect of the cleaning agent can be enhanced. .
Further, when the cleaning agent is injected and the screen is rotated, the contaminants can be more effectively removed by appropriately rotating the screen in the reverse direction.

Further, as the cleaning agent used in the present invention, an alkaline agent such as caustic soda and a synthetic surfactant were not much different in the cleaning effect of the screen 8 as compared with the present cleaning agent mainly containing lipase. However, when biological treatment is performed in the latter stage, problems such as pH rise and foaming occur. On the other hand, in the case of the present lipase-based detergent, there was no adverse effect even when biological treatment was carried out in the subsequent stage. Furthermore, since alkaline agents such as caustic soda and synthetic surfactants simply solubilize and disperse fats and oils, a large proportion remained after biological treatment at the latter stage, whereas lipase was the main constituent. In the case of this cleaning agent
The lipase decomposes the oil and fat to lower the molecular weight, which improves the oil and fat decomposition efficiency. Incidentally, the present invention, in addition to fats and oils,
It can be applied to scale by inorganic substances, contamination by biological slime and fiber, and removal of clogging. The cleaning agent used in this case may be appropriately selected depending on the main substance causing the clogging.

[0015]

As described above, according to the present invention, contaminants adhering to the drum screen can be easily and effectively removed. In addition, when a detergent mainly containing lipase is used, it does not have any adverse effect on the biological treatment step in the subsequent stage. The specific effects of the present invention are listed below. (1) A sufficient amount of cleaning agent can be brought into contact with the screen for immersion. (2) By rotating, the cleaning agent can always be brought into contact with the entire screen in a sufficient amount.

(3) Since the cleaning agent can be uniformly mixed by the rotation, the effect is even. (4) By rotating the screen and moving through the cleaning agent, the adhered contaminants can be physically peeled off. (5) It is economical because the cleaning agent is not transiently consumed. (6) In the case of a screen to which fats and oils are attached, the use of lipase has no adverse effect on biological treatment and can improve the fats and oils degradability of activated sludge. (7) The effect can be obtained by a simple improvement.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a drum screen showing an example of the present invention.

FIG. 2 is a sectional view of an essential part of a drum screen of the present invention.

FIG. 3 is a schematic view showing a supply system of a cleaning agent for a drum screen of the present invention.

FIG. 4 is a process diagram of sludge treatment using the drum screen of the present invention.

[Explanation of symbols]

1: septic tank sludge, 2: receiving tank, 3: drum screen,
4: Storage tank, 5: Biological treatment process, 6: Screw press, 7: Body cover, 8: Screen, 9: Raw water supply pipe, 10: Filtration pipe (liquid discharge pipe), 11: Overflow pipe (liquid discharge pipe) , 12: valve (for filtration tube), 13: valve (for overflow tube), 14: cleaning agent supply tube, 1
5: High pressure washing water pipe, 16: High pressure washing water injection nozzle, 1
7: Water supply pipe, 18: High-pressure washing pump, 19: Solution pipe, 2
0: injection pump, 21: cleaning agent tank, 22: valve (for cleaning agent supply), 23: level sensor, 24: control device,

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayuki Suzuki 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company EBARA Research Institute

Claims (2)

[Claims] 1. A method for cleaning a drum screen, comprising immersing at least a bottom portion of a screen portion of the drum screen in a cleaning agent and rotating the drum screen. 2. A drum screen capable of cleaning a screen portion, a valve provided in a liquid discharge pipe portion near the drum screen, a cleaning agent tank installed outside, and a cleaning agent injected from the tank into the drum screen. An apparatus for cleaning a drum screen, comprising: